-LRB- CNN -RRB- James Holmes made his introduction to the world in a Colorado cinema filled with spectators watching a midnight showing of the new Batman movie , `` The Dark Knight Rises , '' in June 2012 .

The moment became one of the deadliest shootings in U.S. history .

Holmes is accused of opening fire on the crowd , killing 12 people and injuring or maiming 70 others in Aurora , a suburb of Denver .

Holmes appeared like a comic book character : He resembled the Joker , with red-orange hair , similar to the late actor Heath Ledger 's portrayal of the villain in an earlier Batman movie , authorities said .

But Holmes was hardly a cartoon . Authorities said he wore body armor and carried several guns , including an AR-15 rifle , with lots of ammo . He also wore a gas mask .

Holmes says he was insane at the time of the shootings , and that is his legal defense and court plea : not guilty by reason of insanity . Prosecutors are n't swayed and will seek the death penalty .

Opening statements in his trial are scheduled to begin Monday .

Holmes admits to the shootings but says he was suffering `` a psychotic episode '' at the time , according to court papers filed in July 2013 by the state public defenders , Daniel King and Tamara A. Brady .

Evidence `` revealed thus far in the case supports the defense 's position that Mr. Holmes suffers from a severe mental illness and was in the throes of a psychotic episode when he committed the acts that resulted in the tragic loss of life and injuries sustained by moviegoers on July 20 , 2012 , '' the public defenders wrote .

Holmes no longer looks like a dazed Joker , as he did in his first appearance before a judge in 2012 . He appeared dramatically different in January when jury selection began for his trial : 9,000 potential jurors were summoned for duty , described as one of the nation 's largest jury calls .

Holmes now has a cleaner look , with a mustache , button-down shirt and khaki pants . In January , he had a beard and eyeglasses .

If this new image sounds like one of an academician , it may be because Holmes , now 27 , once was one .

Just before the shooting , Holmes was a doctoral student in neuroscience , and he was studying how the brain works , with his schooling funded by a U.S. government grant .

Yet for all his learning , Holmes apparently lacked the capacity to command his own mind , according to the case against him .

A jury will ultimately decide Holmes ' fate . That panel is made up of 12 jurors and 12 alternates . They are 19 women and five men , and almost all are white and middle-aged . The trial could last until autumn .

When jury summonses were issued in January , each potential juror stood a 0.2 % chance of being selected , District Attorney George Brauchler told the final jury this month .

He described the approaching trial as `` four to five months of a horrible roller coaster through the worst haunted house you can imagine . ''

The jury will have to render verdicts on each of the 165 counts against Holmes , including murder and attempted murder charges .

Meanwhile , victims and their relatives are challenging all media outlets `` to stop the gratuitous use of the name and likeness of mass killers , thereby depriving violent individuals the media celebrity and media spotlight they so crave , '' the No Notoriety group says . They are joined by victims from eight other mass shootings in recent U.S. history .

Raised in central coastal California and in San Diego , James Eagan Holmes is the son of a mathematician father noted for his work at the FICO firm that provides credit scores and a registered nurse mother , according to the U-T San Diego newspaper . Holmes also has a sister , Chris , a musician , who 's five years younger , the newspaper said .

His childhood classmates remember him as a clean-cut , bespectacled boy with an `` exemplary '' character who `` never gave any trouble , and never got in trouble himself , '' The Salinas Californian reported .

His family then moved down the California coast , where Holmes grew up in the San Diego-area neighborhood of Rancho Peñasquitos , which a neighbor described as `` kind of like Mayberry , '' the San Diego newspaper said .

Holmes attended Westview High School , which says its school district sits in `` a primarily middle - to upper-middle-income residential community . ''

There , Holmes ran cross-country , played soccer and later worked at a biotechnology internship at the Salk Institute and Miramar College , which attracts academically talented students .

By then , his peers described him as standoffish and a bit of a wiseacre , the San Diego newspaper said .

Holmes attended college fairly close to home , in a neighboring area known as Southern California 's `` inland empire '' because it 's more than an hour 's drive from the coast , in a warm , low-desert climate .

He entered the University of California , Riverside , in 2006 as a scholarship student .

In 2008 he was a summer camp counselor for disadvantaged children , age 7 to 14 , at Camp Max Straus , run by Jewish Big Brothers Big Sisters of Los Angeles .

He graduated from UC Riverside in 2010 with the highest honors and a bachelor 's degree in neuroscience .

`` Academically , he was at the top of the top , '' Chancellor Timothy P. White said .

He seemed destined for even higher achievement .

By 2011 , he had enrolled as a doctoral student in the neuroscience program at the University of Colorado Anschutz Medical Campus in Aurora , the largest academic health center in the Rocky Mountain region .

The doctoral in neuroscience program attended by Holmes focuses on how the brain works , with an emphasis on processing of information , behavior , learning and memory .

Holmes was one of six pre-thesis Ph.D. students in the program who were awarded a neuroscience training grant from the National Institutes of Health . The grant rewards outstanding neuroscientists who will make major contributions to neurobiology .

A syllabus that listed Holmes as a student at the medical school shows he was to have delivered a presentation about microRNA biomarkers .

But Holmes struggled , and his own mental health took an ominous turn .

In March 2012 , he told a classmate he wanted to kill people , and that he would do so `` when his life was over , '' court documents said .

Holmes was `` denied access to the school after June 12 , 2012 , after he made threats to a professor , '' according to court documents .

About that time , Holmes was a patient of University of Colorado psychiatrist Lynne Fenton .

Fenton was so concerned about Holmes ' behavior that she mentioned it to her colleagues , saying he could be a danger to others , CNN affiliate KMGH-TV reported , citing sources with knowledge of the investigation .

Fenton 's concerns surfaced in early June , sources told the Denver station .

Holmes began to fantasize about killing `` a lot of people '' in early June , nearly six weeks before the shootings , the station reported , citing unidentified sources familiar with the investigation .

Holmes ' psychiatrist contacted several members of a `` behavioral evaluation and threat assessment '' team to say Holmes could be a danger to others , the station reported . At issue was whether to order Holmes held for 72 hours to be evaluated by mental health professionals , the station reported .

`` Fenton made initial phone calls about engaging the BETA team '' in `` the first 10 days '' of June , but it `` never came together '' because in the period Fenton was having conversations with team members , Holmes began the process of dropping out of school , a source told KMGH .

Defense attorneys have rejected the prosecution 's assertions that Holmes was barred from campus . Citing statements from the university , Holmes ' attorneys have argued that his access was revoked because that 's normal procedure when a student drops enrollment .

What caused this turn for the worse for Holmes has yet to be clearly detailed .

In the months before the shooting , he bought four weapons and more than 6,000 rounds of ammunition , authorities said .

Police said he also booby-trapped his third-floor apartment with explosives , but police were n't fooled . After Holmes was caught in the cinema parking lot immediately after the shooting , bomb technicians went to the apartment and neutralized the explosives . No one was injured at the apartment building .

Nine minutes before Holmes went into the movie theater , he called a University of Colorado switchboard , public defender Brady has said in court . The number he called can be used to get in contact with faculty members during off hours , Brady said .

Court documents have also revealed that investigators have obtained text messages that Holmes exchanged with someone before the shooting . That person was not named , and the content of the texts has not been made public .

According to The New York Times , Holmes sent a text message to a fellow graduate student , a woman , about two weeks before the shooting .

She asked if he had left Aurora yet , reported the newspaper , which did n't identify her .

No , he had two months left on his lease , Holmes wrote back , according to the Times .

He asked if she had heard of `` dysphoric mania , '' a form of bipolar disorder marked by the highs of mania and the dark and sometimes paranoid delusions of major depression .

The woman asked if the disorder could be managed with treatment .

`` It was , '' Holmes wrote her , according to the Times . But he warned she should stay away from him `` because I am bad news , '' the newspaper reported .

It was her last contact with Holmes .

After the shooting , Holmes ' family issued a brief statement : `` Our hearts go out to those who were involved in this tragedy and to the families and friends of those involved , '' they said , without giving any information about their son .

Since then , prosecutors have refused to offer a plea deal to Holmes .

For Holmes , `` justice is death , '' said Brauchler , the district attorney .

In December , Holmes ' parents , who will be attending the trial , issued another statement : They asked that their son 's life be spared and that he be sent to an institution for mentally ill people for the rest of his life , if he 's found not guilty by reason of insanity .

`` He is not a monster , '' Robert and Arlene Holmes wrote , saying the death penalty is `` morally wrong , especially when the condemned is mentally ill . ''

`` He is a human being gripped by a severe mental illness , '' the parents said .

The matter will be settled by the jury .

CNN 's Ana Cabrera and Sara Weisfeldt contributed to this report from Denver .

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Opening statements are scheduled Monday in the trial of James Holmes

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Jury selection took three months

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Holmes faces 165 counts in the movie theater massacre that killed 12 people